From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755422AbbIINbK (ORCPT ); Wed, 9 Sep 2015 09:31:10 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:44499 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753989AbbIINau (ORCPT ); Wed, 9 Sep 2015 09:30:50 -0400 Message-ID: <55F03482.4030104@roeck-us.net> Date: Wed, 09 Sep 2015 06:30:42 -0700 From: Guenter Roeck User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 MIME-Version: 1.0 To: =?windows-1252?Q?Emilio_L=F3pez?= , Greg KH CC: olof@lixom.net, kgene@kernel.org, k.kozlowski@samsung.com, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org Subject: Re: [PATCH 1/3] sysfs: Fix is_visible() support for binary attributes References: <1441714066-5599-1-git-send-email-emilio.lopez@collabora.co.uk> <1441714066-5599-2-git-send-email-emilio.lopez@collabora.co.uk> <20150908153013.GA6758@roeck-us.net> <20150908191002.GB10156@kroah.com> <20150908193052.GA11106@roeck-us.net> <55EF82A4.5000502@collabora.co.uk> <55EF86F8.3060406@roeck-us.net> <20150909035850.GA5497@kroah.com> <55EFB1B5.1060703@roeck-us.net> <55F030C6.80504@collabora.co.uk> In-Reply-To: <55F030C6.80504@collabora.co.uk> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/09/2015 06:14 AM, Emilio López wrote: > On 09/09/15 01:12, Guenter Roeck wrote: >> On 09/08/2015 08:58 PM, Greg KH wrote: >>> On Tue, Sep 08, 2015 at 06:10:16PM -0700, Guenter Roeck wrote: >>>> Hi Emilio, >>>> >>>> On 09/08/2015 05:51 PM, Emilio López wrote: >>>>> Hi Greg & Guenter, >>>>> >>>> [ ... ] >>>>>>>> >>>>>>>> Unless I am missing something, this is not explained anywhere, >>>>>>>> but it is >>>>>>>> not entirely trivial to understand. I think it should be documented. >>>>> >>>>> I agree. I couldn't find any mention of what this int was supposed >>>>> to be by looking at Documentation/ (is_visible is not even mentioned >>>>> :/) or include/linux/sysfs.h. Once we settle on something I'll >>>>> document it before sending a v2. >>>>> >>>> In the include file ? No strong preference, though. >>>> >>>>> By the way, I wrote a quick coccinelle script to match is_visible() >>>>> users which reference the index (included below), and it found >>>>> references to drivers which do not seem to use any binary >>>>> attributes, so I believe changing the index meaning shouldn't be an >>>>> issue. >>>>> >>>> Good. >>>> >>>>>>> I agree, make i the number of the bin attribute and that should solve >>>>>>> this issue. >>>>>>> >>>>>> No, that would conflict with the "normal" use of is_visible for >>>>>> non-binary >>>>>> attributes, and make the index all but useless, since the >>>>>> is_visible function >>>>>> would have to search through all the attributes anyway to figure >>>>>> out which one >>>>>> is being checked. >>>>> >>>>> Yeah, using the same indexes would be somewhat pointless, although >>>>> not many seem to be using it anyway (only 14 files matched). Others >>>>> seem to be comparing the attr* instead. An alternative would be to >>>>> use negative indexes for binary attributes and positive indexes for >>>>> normal attributes. >>>>> >>>> ... and I probably wrote or reviewed a significant percentage of >>>> those ;-). >>>> >>>> Using negative numbers for binary attributes is an interesting idea. >>>> Kind of unusual, though. Greg, any thoughts on that ? >>> >>> Ick, no, that's a mess, maybe we just could drop the index alltogether? >>> >> >> No, please don't. Having to manually compare dozens of index pointers >> would be >> even more of a mess. > > So, what about keeping it the way it is in the patch, and documenting it thoroughly? Otherwise, we could introduce another "is_bin_visible" function to do this same thing but just on binary attributes, but I'd rather not add a new function pointer if possible. > I would prefer to keep and document it. Guenter